Although there are many different kinds of locks available on the market today, only the tubular lock, because of its special design and number of different lock combinations, is consistently installed in motorcycles, suitcases, burglar alarm devices, electrical code controllers, locks on trunks, frames, doors, windows, etc. The construction of the standard tubular lock is as follows: in FIGS. 6 and 7, flange portion (a) is fixed on the lock shaft (b). In the flange pin holes (d) on the flange portion (a), there are several flange lock pins (c) of different lengths. In the plug pin grooves (f) on the plug (e) there are springs (g) and several plug lock pins (h) of equal length. When putting lock shaft (b) through plug (e) and stop lump (k), every flange lock pin (c) is lined up with every plug lock pin (h), allowing plug lock pin (h) to pass through the flange pin hole (d) on the flange portion (a). Flange portion (a) and plug (e) are installed in the outer shell (i), and plug (e) is fixed by the fixing pin (y) through the fixing hole (z) on the outer shell (i). The upper end of the flange lock pin (c) rests against the interior of the flange of outer shell (i), as shown in FIG. 7. Since plug (e) is fixed in the outer shell (i) and plug lock pin (h) passes through the flange pin hole (d), the flange portion (a) is locked into position by the plug lock pin (h), and cannot be turned in the outer shell (i).
As shown in FIG. 6, there are several pin push grooves (m) of different depths on key (j). In the hollow interior of the key, there is a key pillar (v) (see FIG. 6-1). This key pillar (v) can be inserted in the rectangular groove (n) of lock shaft (b). When turning key (j), lock shaft (b) and flange portion (a) are driven to turn simultaneously (see FIG. 8). When key (j) is inserted into the outer shell (i), the bottoms of the pin push grooves (m) of different depths contact the upper ends of the flange lock pins (c), and drive the flange lock pins (c) and plug lock pins (h). When the fore-end of key (j) touches flange portion (a), every plug lock pin (h) is returned to plug pin groove (f) of plug (e) (flange lock pin (c) does not enter plug pin groove (f) of plug (e)). Then, turning key (j) makes lock shaft (b) and flange portion (a) turn in the outer shell (i) (plug (e) does not turn). In this way, the tubular lock can be opened. By turning shaft (b), the lock latch (s) can be driven to lock. Scewcap (t) is used to fix lock latch (s) and stop lump (k) (see FIG. 9 which is a side view of FIG. 8). When lock shaft (b) is turned stop lump (k) is also turned. When the stop mouth (p) of stop lump (k) touches the stop pillar (q) of plug (e), the stop pillar (q) will bar the key (j) from continuing to turn. Stop lump (k) is designed to prevent the turning angle of key (j) from extending the set limit.
FIG. 13 is a detailed drawing of flange lock pin (c) in flange pin hole (d), and plug lock pin (h) in plug groove (f). At the interface of flange pin hole (d) and plug pin groove (f) of a standard tubular lock, there are small rounded corners (d.sub.1) (f.sub.1) respectively. The functions of the small rounded corners (d.sub.1) (f.sub.1) are as follows: when manufacturing tubular locks, the construction must be extremely accurate, but it is very difficult to match exactly the pin push groove (m), flange lock pin (c), plug lock pin (h), flange portion (a), plug (e), etc. Thus, a small rounded corner is usually designed, to compensate for possible error when manufacturing the flange lock pin (c) and plug lock pin (h), flange portion (a), plug (e), etc. This allows smoother operation. For example: when key (j) is inserted to open the tubular lock the upper end (h.sub.1) of plug lock pin (h) is not exactly on the interface of the plug (e) and flange portion (a). The common situation is where an extremely small portion of the upper end of plug lock pin (h.sub.1) is in flange pin hole (d), or an extremely small portion of the upper end of flange lock pin (c) is in plug pin groove (f). When this happens, if key (j) is turned making flange portion (a) rotate, the upper end (h.sub.1) of plug lock pin (h) will touch the small rounded corner (d.sub.1) which pushes plug lock pin (h) into plug pin groove (f), permitting the lock to open.
Another design feature to compensate for error during manufacture is that the diameters of the flange pin hole (d) and plug pin groove (f) are made slightly larger than those of flange lock pin (c) and plug lock pin (h). If the diameter of flange pin hole (d) and plug pin groove (f) is 2.1 mm, the diameter of flange lock pin (c) and lower lock pin (h) will be about 2 mm. Therefore, there is a gap of 0.1 mm between lock pin and pin hole. This space allows flange portion (a) to turn right or left up to 0.1 mm.
The standard tubular lock can be easily opened by lock experts who use a special pick tools (FIGS. 5 & 14). The standard tubular lock then, is exposed to either burglars or experts, both of whom are capable of easily opening the lock.
FIG. 14 shows the slightly backward and release method pick tool or pick master which is equipped with steel pins (f) corresponding in number to the pins of the lock. The steel pin control-ring (con-ring) uses a screw-and-rubber-ring tightening method to control steel pins (r) and a resistance and floating ring to increase or decrease the movement of the steel pins. As demonstrated in FIGS. 10, 11 and 12, pushing these steel pins (r) separately into each flange pin hole (d), and pushing flange lock pin (c) causes plug lock pin (h) to be pushed down to the bottom of plug pin groove (f) (FIG. 10). Then, this pick tool is turned right or left continuously (it can be slightly turned because of space between the pins and the walls of the holes). The compressed springs (g) in the lock push the plug lock pin (h), the plug lock pin in turn, pushes the flange lock pin (c), and the flange lock pin (c) then pushes the steel pin (r) of the pick tool, and the steel pin (r) will withdraw. Furthermore, because the withdrawal of the steel pins (r) is controlled by the conring, every steel pin withdraws very slowly until one of the steel pins reaches the point where the ends (h.sub.1) of the plug lock pins (h) are even with the openings of the plug pin grooves (f) (FIG. 12). Because flange portion (a) is continuously turned right or left by the pick tool, plug lock pin (h) moves upward and stops only when the upper end of the plug lock pin (h.sub.1) touches the small round corner (d.sub.1) of the flange pin groove (see FIG. 16). When the steel pins (r) drive flange portion (a) to turn right or left, plug lock pin (h) will touch the small rounded corner (d.sub.1) continuously. But, as shown in FIG. 12, if the ends of the other plug pins (h.sub.1) are not even with openings of the plug pin grooves, the lock pins (h) will continue to rise. Thus, only when the ends of the plug lock pins are even with the openings of the plug pin grooves, as shown in FIG. 11, is it possible to make the steel pins (r) turn the flange portion (a) to open the tubular lock.
The error-measuring pick tool is shown in FIG. 5. This tool is also equipped with steel pins (r') corresponding to the pins of the lock. The steel pins (r') are used to push flange lock pin (c) forward (FIG. 15). As with the pick master, the steel pins (r') are continuously turned to the right or left (as stated above, there is a gap of 0.1 mm between lock pin and pin hole wall), to make flange portion (a) move. When flange lock pin (c) touches the small rounded corner (f.sub.1) it can be felt by hand. Then, the depth of the insertion of the steel pin (r') is recorded. One by one the other steel pins are pushed against other flange lock pins and the depths of the insertions of all steel pins are recorded. In this way, the depth necessary to make each steel pin push each plug lock pin into its plug pin groove is determined. Likewise, it can be measured whether each flange lock pin (c) fits exactly in its flange pin hole (d) and whether each plug lock pin (h) is in the correct position in its plug pin groove. Thus, by turning steel pins (r'), the flange portion can be turned and the lock opened. Although pick tools can be used to take advantage of the error between the hole and pin and the synchronization of the corners (d.sub.1) or (f.sub.1) to open the standard tubular lock, the tubular lock of the present invention prevents a burglar from taking advantage of these design characteristics.